hislop



G. R. HISLOP. Revivifying Spent Lime.

Patented-July 8,1879.

Y in.; o o 0 /y MIL/@ N- PETERS, PNDTO-LITIOGRAHER. WASHINGTON, D. C.

sT-ATES einem' oFF-ICE.

` GEORGE R. HISLOPpOF PAISLEY, COUNTY OF RENFREVfNORTH BRITAIN.

IMPROVEMENT IN REVIVIFYING SPENT LIME..

Specification forming part of Letters Patent No. 217377, dated July 8, 1879 application filed JuneI 18, 1879.

To all whom i't may concern Be it known that I, GEoRcE ROBERTSON HIsLOP, of Paisley, in the county of Renfrew, North Britain, have invented Improvements i in Revivifying Spent Lime, of which the folfrom a furnace wherein carbonaceous matter,` v "1n the solid, liquid, or gaseous state, is burned.

In practicing my invention it is desirable to 4bring the products of combustion into as intimate contact as possible with the spent1ime under treatment, and to present as great a surface of the'lime as may be to the said products of combustion. n

Y My invention may be carried into effect with several forms of apparatus consisting of chambers; but it is explained that my invention does not consist in the form or arrangement o f the chambers, but in the process conducted in the said chamber or chambers. .The spent lime is fed into an apparatus consisting of` a chamber or chambers to contain the lime, the chamber or chambers being in communication at one end with a furnace in which carbonaceous matter is-burned,'and at the otherend in communication with a chimney orother outlet, so that the products of combustion from the furnace pass over and in contact' with the lime in the chamber or chambers on'their way to the chimney or outlet. The chambers are preferably of but small diameter or depth, and in the case of a number of chambers they are so set or arranged that they communicate the one with the other at each end, so as to form a continuous passage for the products of combustion from one chamber to another, and so through all the chambers from the furnace to the chimney or outlet.

I here describe some arrangements of chambers by which the process constituting my invention may be successfully practiced.

Figure l of the accompanying drawings repabove the other, as shown.

resents in longitudinal vertical section, and Fig. 2 partly in elevation and partly in transverse section, an arrangement of chamber suitable for carrying the process constituting` my invention into effect.

The said chambers are shown in duplicate; but, as both sets are of the same construction, the description of one set will suffice.

The chambers A Al A2 A3 arebuilt one The chamber A, at the top, is a drying-chamber, and` the others are calcining or revivifying chambers. A

furnace, B, is in communication with the chambers by means of the flues a a, alternately, at either end of the chambers, so that the products of combustion from the said furnace pass throughall the chambers in the presence of the lime, as indicated. by the arrows. The chambers areeach furnished with doors B',

`forthe insertion of tools and the introduction,

spreading, or withdrawal of thelime.

The bottoms of the chambers A Al A2 have openings a therein for the passage of the lime; from chamber to chamber, the said openings being covered by tiles.

The spent lime to be treated is fed into the `c hai'nberA through the hopper C., and is there dried or partially treated; and from this chamber the lime is passed through the openings a in the bottom thereof into the chamber A1, and so on until all of the chambers have received such a charge as will allow free passage for the products of combustion above them. When the treatment ofthe lime in the three lower chambers, A1 A2 A3, is completed it is removed and the contents of the chamber A are discharged thereinto.

For the purpose of regulating the temperature of the dii'ere'nt chambers or parts of the chambers air is admitted 4thereto by ventilatin g-boxes, marked C lin Fig. 2 of the drawings,

by means of which boxes the air may be admitted to, controlled in, or cnt oft at any part ofthe apparatus.

Fig. 3 represents in longitudinal vertical section another arrangement ot' apparatus suited for the purposes of practicing the process constituting my invention.

B is the fire-place, from which the products of combustion pass through the series of chambers D E FG, the part D being the finishingsole; E, the lower retort; F, the upper re tort, and G. the hopper, the said products passing by the flues H down the sides off the retort to the flue Hl beneath, then up to the flue H2, and thence to the chimney. The spent lime is fed into the retort at Iand the finished.l lime is drawn out at K.

The retort contains ive charges at one time,- viz: one on the sole D, one in the lower, andl one in the upper retort, E F, and two in the hopper G. By means of rakes passed throughthe door J these charges are successively drawn and pushed forward one remove, and' as each remove is made a fresh charge is inserted into the hopper G, so that all the charges pass successively from the hopper Gr to the retort F, thence to the retort E, thence to the sole-plate D, and are nally withdrawn from the chamber.

Two or any number of these chambers may be combined in one setting.

In' order to present a larger surface of lime to the action of the products of combustion the chambers in which the revivifying prothe sources referred to on beingpassed' through cess is carried on may be made to rotate, if desired, being then preferably made circular, audit may be in the form of one long tube, and the lime may be caused to pass slowly and continuously down through the chamber or chambers by setting them at an inclination,l the lower end being that at which the furnace is situated, so that the lime and the products of combustion pass in reverse directions.

Instead of giving motion of rotation to the cylinders or chambers they may receive anoscillatory motion, when a. suitable shape in crosssection will be that of an ellipse.

A jet of saturated or superheated'steammay be used to assist the products of combustion in their revivifying action, the said steam being preferably injected at the lower end of the cylinders or chambers or into the furnace.

In the process of revivifying lime, as hereinbefore described, the lime, when at the-part ofthe chamber or chambers farthest fromthe furnacethat is, at the first part of its treatment-'is desulphurizedby the carbonic acidi discharged from the lime at the part of the chamber or chambers near to the furnace by the intense heat at that part.

When oxide of iron is employed the foul lime, being in a state of l carbonate, can be revived at once, and may be used and revived a great number of times; but where no oxide j of ironA is used the foul lime is largely charged with` sulphur, as well as with; carbonic acid and other impurities, and cannot be reused and revived nearly so frequently as can the lime where oxide of iron is used or otherwise produced in the form of carbonate. In order' to. render this lime more durable, the wastegases from the retort-furnaces, steam-boiler furnaces,or the calcining-chambers themselves,

consisting chiefly of carbonio-acid gas, are drawn by a pump or other suitable means, and

forced up through the spent lime in the puri fier after it has been shut off from the gas as fouled.ik 1

The passages or pipes are provided with the necessary back-draft valves.

The carbonio-acid gas from the furnaces, before they enter the purifier, are cooled to 1500 Fahrenheit, or to. a lower temperature, by passing them through a cold-water or other condenser on their way to the purifier.

A small jet of steam may be injected along with` the furnace-gases into. the purifier.

By this process the carbonic-acidIl gas from the sulphureted lime in the purifier displaces the sulphur,chiefiy in the form of sulphureted hydrogen, and combines with the lime, form- 'ing lime carbonate, and the discharged gasesfrom the fouled purifier may be passed through 'oxide of 'ironin order that it may absorb thev sulphur. The lime thus carbonated, is treatedY sin calcining-chambers, as hereinbefore described', and revivied.

I claiml. The process of revivifying spent lime by,

submitting it to the direct action of the products of combustion from a. furnace whereincarbonaceous matter is burned, also assisting the action` of the said products by a jet or jets l of saturated or superheated steam.

2. The hereinbefore-described treatment of vspent lime to prepare it for recalcinationnamely, desulphurizing it by passing furnacegases through it while inthe purifiers.-

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

GEORGE ROBERTSON. HISLOP. [1.. s.] Witnesses:

ROBERT ADAM GzUNN,

115 St. Vincent Street, Glasgow. JAMES SMITH BEGG,

115 St. Vincent Street, Glasgow. 

